Telephone-exchange apparatus.



PATENTED JULY 25, 1905.

I. R. MoBBRTY.

TELEPHONE EXCHANGE APPARATUS.

APPLICATION FILED SEPT. 28. 1903.

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UNITED STATES PATENT OFFICE.

FRANK R. MGBERTY, OF EVANSTON, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

Specification of Letters Patent.

Patented July 25, 1905.

Application filed September 28,1903. Serial No. 174,900.

To all whmn it may concern.-

Be it known that I, FRANK R. MoBnR'rY, a citizen of the United States, residingatEvanston, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in 'lelephone-Exchange Apparatus, of which the following is a full, clear, concise, and exact description.

My invention relates to telephone-exchange systems, and has for its object to provide improved and simplified apparatus for controlling the automatic signals at the central oflice.

In accordance with my invention the linesignal apparatus at the central office is included n one branch of the line controlled by the contacts of a cut-off relay, the magnet of which relay is included in another branch, which is normally open, extending to a springjaek or other connection-terminal for the line. \Vhen a circuit such as the operators plugcircuitincluding a battery is brought into connection with the line by way of the terminal switch thereof, the cut-off relay is thus included in the path of current controlled by the substation-switch and being excited acts to disconnect the branch containing the linesignal apparatus.

A further feature of the invention lies in the provision of circuits and apparatus for bringing a supervisory signal temporarily under the control of the aforesaid cut-off relay, whereby a special supervisory relay in the operators circuit is rendered unnecessary.

I will explain my invention by reference to the accompanying drawing, and the features or combinations which I regard as novel will be pointed out in the appended claims.

The drawing represents in diagram two telephone-lines extending from substations to a central-oflice switchboard, the system being organized and equipped for automatic control of signals in accordance with my invention.

Each line consists of two limbs or conductors 1 2, leading-from the usual substation apparatus to the line-springs a a, respectively, of the spring-jack or connection-terminal a. The usual automatic telephone-switch s is provided at the substation controlling the bridge of the line conductors which includes the telephone transmitting and receiving apparatus. At the central ofiice the usual central battery Z) is included, together with the line-relay 0, in a branch 3 4c of the line-circuit, said branch being controlled at the normally closed contacts cl (Z of a cut-off relay (Z. The linerelay 0 controls at its front contact a local circuit 5, containing the incandescent lamp 0', which serves as a call-indicator. The magnet of the cut-off relay (Z is included in the line conductor 2 between the spring a of the jack and the connection of the branch 3 4:, which contains the line-signal-controlling apparatus. The magnet of the cut-off relay may be permanently shunted by a non-inductive resistance.

A pair of plugs e 0 is illustrated, each plug having the usual tip, ring, and sleeve contacts a 0 6 respectively, the tip and ring contacts of each plug being united with the corresponding contacts of its mate by conductors 6 7, which include the windings of the usual repeating-coil. The battery I) is connected, as usual, in a bridge of the plug-circuit between the windings of the repeatingcoil. \Vhile three batteries(marked 7))are shown in the drawing, it is understood, of course, that in accordance with the usual practice a single battery may be employed, which may be connected as indicated.

A supervisory signal f, which may be an incandescent lamp, is connected in a ground branch from the third contact or sleeve 0" of each plu The test-ring or third contact a of the jack with which the contact a" of the plug is adapted to register is connected through a resistance with the free pole of the grounded battery 5 and is also connected by a conductor 8 to a front contact of the armature d of the cut-off relay.

The operation of the system is as follows: The subscriber transmits a call in the usual way by removing his telephone-receiver from its hook, whereby a bridge of the line is antomatically closed by the switch 8 and the line-relay 0 receives current and bringsabout the illumination of the line signal-lamp 0. When the operator responds to the call by inserting an answering-plug in the springjack (0, the batteryb is applied to the line over the conductors 6 7 of the cord-circuit and the magnet of the cut-off relay d, which is interposed serially in the conductor 2, is excited and draws up its armatures, cutting off the branch 3 4, which contains the linesignal apparatus, and connecting the grounded wire 3 with the third contact a of the jack by way of the conductor 8. When the plug is inserted in the jack, the supervisory lamp f associated with that plug is brought under the control of the cut-off relay (Z of the line whose jack is plugged into, said cut-off relay being arranged to close the shunt 8 3 about the lamp when excited. As long as the subscriber at the substation is using his telephone the supervisory lamp f will be shunted out; but when he replaces his telephone on its book the circuit through the magnet of the cut-off relay is opened, so that said relay allows its armature to fall back, breaking the shunt 8 3, and so causing increased current to flow through the supervisory lamp to cause its illumination.

Havingthus described my invention, I. claim as new, and desire to secure by Letters Patent, the following:

1. The combination with a telephone-line extending from a substation to a central station, of line-signal apparatus in the circuit of said line at the central station, a switch at the substation for controlling said line-signal apparatus, and a cut-off relay in said line-circuit when the same is switched under the control of said substationswitch, said relay controlling the continuity of the circuit through the line-signal apparatus.

2. The combination with a telephone-line extending between a substation and a central station, and a circuit-controlling switch therefor at the substation, of a normally closed branch of said line at the central station containing line-signal apparatus responsive to said circuit-controlling switch, a normally open alternative branch of said line also at the central station containing a cut-off relay controlling the connection with said line of said normally closed branch, and switch devices at said central station adapted to close said normally open branch through a source of current for the operation of said relay and to bring the same under the control of the substation-switch, substantially as set forth.

3. The combination with a telephone-line extending from a substation to a central oflice, of a line-signal device and a battery in a branch of the line at the central office, a telephoneswitch at the substation controlling the linecircuit, a connection-terminal for the line at the central office, a central-office circuit including a battery adapted to be brought into connection therewith, and a cut-off relay havin g switch-contacts for disconnecting the linesignal apparatus, said relay being serially included in the line between said connection-terminal and the branch containing the line-signal device and brought under the control of said substation-switch upon the connection of said central-office circuit with the line.

L. The combination with a telephone-line extending from a substation to a central oflice, of a branch at the central office containing the battery and a line-signal device, a telephoneswitch 8 controlling the circuit at the substation, a connection-terminal for the line at the central office, a loop-circuit containing a battery adapted to be brought into connection with the line at said terminal, a cut-off relay included in the line-circuit to be operated by the current from the battery in said loop-circuit, said eut-o'lf relay controlling the connection of the line-signal tDPiLliLlJUS, and a supervisory signal temporarily associated with the line during connection, controlled by the cut-off relay.

5. The combination with a telephone-line extending from a substation to a spring-jack at a central-office switchboard, of a battery and a line-signal device in a branch of the line at the central office, a telephone-switch controlling a bridge of the line at the substation, a plug and plug-circuit at the central office for making connection with the line at the spring-jack thereof, a battery in a bridge of the plug-circuit, a cut-off relay controlling the branch which contains the line-signal device,

included in the line between the spring-jack and the branch containing said line-signal device, a supervisory signal in a local circuit established in registering contacts of the plug and spring-jack, and a shunt for said supervisory signal controlled by switch-contacts of the cut-off relay.

6. The combination with a telephone-line extending in two limbs from a substation to a central-office battery, of a substation-switch controlling the line-circuit, a line-signal in the line-circuit at the central office, a spring-jack for the line at the central office and branch conductors leading from the line conductors thereto, a cut-off relay serially included in one of said branch conductors and controlling the connection of said line-signal with the line, a plug for making connection with said spring-jaek,circuit-conductors connected with said plug, and a battery in a bridge of the said conductors adapted to be applied to the line upon the closure of said plug and jack to operate the cut-off relay, said relay being thereupon brought under the control of the substation-switch.

In witness whereof I. hereunto subscribe my name this 19th day of February, A. D. 1902.

FRANK R. MOBERTY.

Vitnesses:

FREDERICK A. VVA'IKINS, EDWIN H. SMY'rIIn. 

